Ever brew Kombucha?

The kombucha scoby is basically yeast and aceter bacteria, the yeast eats the sugar and makes alcohol (I'm sure we're all familiar with that) then the aceter bacteria eats the alcohol and makes acetic acid (vinegar). This is why homebrewers/vintners might not be fans of making kombucha, 5 gallons of vinegar when you were expecting beer or wine is not cool.

I make kombucha in a method similar to what StormerOfLezbos posted, though I brew the tea longer/stronger and add more sugar.The strong brewed tea also supplies nutrients for the culture (yeast can not live on sugar alone). The longer you let it ferment the less sweet and more sour/acidic the tea becomes, also when you're done fermenting and you remove the scoby, note that there will still be yeast (and probably bacteria too) left in your kombucha. So any residual sugar will continue to be consumed, using this knowledge you can put the kombucha in sealed bottles and allow it to carbonate, or you can stick it in the fridge and arrest all fermentation.

I brew beer, but my wife makes Kombucha and Kefir. Its much easier than beer, however I wouldn't recommend mixing equipment. In a nutshell, this is how its done.

1. Boil 3 quarts of water. Remove from heat.
2. Add 4 caffinated teabags and brew for about 5 minutes.
3. Add 1 cup of sugar, stir until disolved.
4. Let your tea cool to room temperature.
5. Pour into glass brewing container and cover with a towel so it can breath.
6. Add your 'scoby' (baby Kombucha) and half cup of tea from a previous batch.
7. Let it brew for at least 7-10 days. The longer it brews the more it will taste like vinegar.
8. At this point you can drink it. Make sure to save a half cup for your next batch.

As you can see it is similar to brewing beer, but much quicker. She doesn't seem to be as worried about cleanliness either. It does produce some alcohol, so your tea can get a bit carbonated depending on how you store it. You notice this more if you store your tea in an airtight container. I bought her some Grolsch style bottles with the rubber stoppers from my LHBS. You can also brew your tea with berries or ginger. Scobies (starter mushrooms) can be had off the internet or craigslist for a couple bucks.

This is obviously just the basics, and there are plenty of good resources on the internet about how to do it. I personally don't care for it, but I do enjoy the Kefir she makes.